The present invention relates to pattern formation material and method. More particularly, it relates to a pattern formation material and a pattern formation method adopted for forming a resist pattern, used for forming a semiconductor device or a semiconductor integrated circuit on a semiconductor substrate, by using light of a wavelength of a 1 nm through 180 nm band.
As exposing light used in forming a resist pattern through pattern exposure of a resist film formed on a semiconductor substrate, KrF excimer laser has been put to practical use. Also, a device including a semiconductor device or a semiconductor integrated circuit formed by using a resist pattern obtained by the pattern exposure using the KrF excimer laser is almost commercially available.
In this case, a resist material including a phenol type resin is mainly used as a resist material to be pattern-exposed with the KrF excimer laser.
For further refinement of a semiconductor device or a semiconductor integrated circuit, ArF excimer laser operating at a shorter wavelength than the KrF excimer laser is used as the exposing light. A resist material including an acrylic acid type resin is mainly under examination as a resist material used in the pattern exposure with the ArF excimer laser.
In order to realize further refinement of a semiconductor device or a semiconductor integrated circuit, however, it is necessary to use, as the exposing light, a laser beam with a wavelength shorter than that of the ArF excimer laser, such as a Xe2 laser beam (with a wavelength of a 172 nm band), a F2 laser beam (with a wavelength of a 157 nm band), a Kr2 laser beam (with a wavelength of a 146 nm band), an ArKr laser beam (with a wavelength of a 134 nm band), an Ar2 laser beam (with a wavelength of a 126 nm band) or a soft X-ray beam (with a wavelength of a 13, 11 or 5 nm band).
Therefore, the present inventors have formed a resist pattern from a resist film of a known resist material through pattern exposure using a F2 laser beam.
However, the resultant resist pattern does not have a rectangular sectional shape but has a defective pattern shape.
In consideration of the aforementioned conventional problem, an object of the invention is forming a resist pattern in a good pattern shape by using light of a wavelength of a 1 nm through 180 nm band as exposing light.
The present inventors have concluded that the resist pattern has a defective pattern shape because the resist film has a high absorbing property against light of a wavelength of a 1 nm through 180 nm band, and variously studied about resist materials for decreasing the absorbing property against light of a wavelength of a 1 nm through 180 nm band. As a result, it has been found that the absorbing property of a resist film against light of a wavelength of a 1 nm through 180 nm band can be decreased when the resist material includes a group for producing an active methylene group through decomposition in the presence of an acid.
Therefore, the inventors have variously studied about a resist material including a group for producing an active methylene group through decomposition in the presence of an acid. As a result, it has been confirmed that the absorbing property against light of a wavelength of a 1 nm through 180 nm band can be decreased by using a resist material including a group for producing an active methylene group through decomposition in the presence of an acid, and found that a resist film formed from such a resist material can be definitely developed even when the concentration of an alkaline developer is low.
The present invention was devised on the basis of the aforementioned findings, and a resist material according to the invention includes a polymer or a compound having a group for producing an active methylene group through decomposition in the presence of an acid.
Specifically, the first pattern formation material of this invention comprises a base polymer including a group for producing an active methylene group through decomposition in the presence of an acid; and an acid generator for generating an acid through irradiation with light.
The first pattern formation method of this invention comprises the steps of forming a resist film by applying, on a substrate, a resist material including a base polymer having a group for producing an active methylene group through decomposition in the presence of an acid and an acid generator for generating an acid through irradiation with light; and forming a resist pattern by irradiating the resist film with exposing light of a wavelength of a 1 nm through 180 nm band for pattern exposure and developing the resist film after the pattern exposure.
In the first pattern formation material or the first pattern formation method, the base polymer includes a group for producing an active methylene group through decomposition in the presence of an acid. Therefore, the absorbing property of the resist film against light of a wavelength of a 1 nm through 180 nm band is generally decreased, resulting in increasing transmittance against the exposing light of a wavelength of a 1 nm through 180 nm band. Accordingly, a resist pattern can be formed in a good pattern shape through pattern exposure using light of a wavelength of a 1 nm through 180 nm band as the exposing light.
Furthermore, since an exposed portion of the resist film can be developed with an alkaline developer even in a low concentration, swelling of an unexposed portion of the resist film can be suppressed. As a result, resist patterns close to each other can be prevented from inclining to be further closer to each other.
The second pattern formation material of this invention comprises a base polymer soluble in an alkaline developer; a dissolution inhibiting agent, including a group for producing an active methylene group through decomposition in the presence of an acid, for inhibiting solubility of the base polymer in an alkaline developer; and an acid generator for generating an acid through irradiation with light.
The second pattern formation method of this invention comprises the steps of forming a resist film by applying, on a substrate, a resist material including a base polymer soluble in an alkaline developer, a dissolution inhibiting agent, including a group for producing an active methylene group through decomposition in the presence of an acid, for inhibiting solubility of the base polymer in an alkaline developer, and an acid generator for generating an acid through irradiation with light; and forming a resist pattern by irradiating the resist film with exposing light of a wavelength of a 1 nm through 180 nm band for pattern exposure and developing the resist film after the pattern exposure.
In the second pattern formation material or the second pattern formation method, the dissolution inhibiting agent includes a group for producing an active methylene group through decomposition in the presence of an acid. Therefore, the absorbing property of the resist film against light of a wavelength of a 1 nm through 180 nm band is generally decreased, resulting in increasing transmittance against the exposing light of a wavelength of a 1 nm through 180 nm band. Accordingly, a resist pattern can be formed in a good pattern shape through pattern exposure using light of a wavelength of a 1 nm through 180 nm band as the exposing light.
Furthermore, since an exposed portion of the resist film can be developed with an alkaline developer even in a low concentration, the swelling of an unexposed portion of the resist film can be suppressed. As a result, resist patterns close to each other can be prevented from inclining to be further closer to each other.
In the first or second pattern formation material or the first or second pattern formation method, the group for producing an active methylene group is preferably represented by General Formula 1, xe2x80x94COxe2x80x94CHxe2x95x90C(OR1)(OR2), wherein R1 and R2 are the same or different substituent or non-substituted groups selected from the group consisting of a saturated alkyl group, an unsaturated alkyl group, a cyclic saturated alkyl group, a cyclic unsaturated alkyl group, a silyl group and a carbonyl group.
In the case where the group for producing an active methylene group is represented by General Formula 1, when an acid (H+) is generated from the acid generator through irradiation with light, the group R1 is eliminated from General Formula 1 to produce an active methylene group as shown in Chemical Reaction Formula 1 below.
Chemical Reaction Formula 1
Specific examples of the group R, eliminated from General Formula 1 are t-butyl, 1-ethoxyethyl, tetrahydropyranyl, t-butyloxycarbonyl, 2-methyl-2-adamantyl and trimethylsilyl, which do not limit the invention.
In the first or second pattern formation material or the first or second pattern formation method, the group for producing an active methylene group is preferably represented by General Formula 2, xe2x80x94C(OR1)xe2x95x90Cxe2x95x90C(OR2)(OR3), wherein R1, R2 and R3 are the same or different substituent or non-substituted groups selected from the group consisting of a saturated alkyl group, an unsaturated alkyl group, a cyclic saturated alkyl group, a cyclic unsaturated alkyl group, a silyl group and a carbonyl group.
In the case where the group for producing an active methylene group is represented by General Formula 2, when an acid (H+) is generated from the acid generator through irradiation with light, the groups R1 and R2are eliminated from General Formula 2 to produce an active methylene group as shown in Chemical Reaction Formula 2 below.
Chemical Reaction Formula 2: 
The specific examples of the groups R1 and R2 eliminated from General Formula 2 are t-butyl, 1-ethoxyethyl, tetrahydropyranyl, t-butyloxycarbonyl, 2-methyl-2-adamantyl and trimethylsilyl, which do not limit the invention.
In the second pattern formation material or method, specific examples of the base polymer are an acrylic type resin, a styrene type resin, a novolak resin and a polyolefin type resin, which do not limit the invention.